Wear resistant grinding machine components

ABSTRACT

Various grinding machine components are made of superhard materials, including certain machine grade ceramics, including such materials as carbides, nitrides, borides, oxides, oxynitrides, or any other ceramic component. The component may either be a solid piece of ceramic or wear resistant material, or may have an insert or a piece of the wear resistant material adhered to a metallic substrate base for use within the machine. Graded materials may also be used with a gradient from a 100% concentration of ceramic at one surface, and gradually changing into a 100% metal at the other surface, would be advantageous. These superhard materials overcome some of the previously experienced problems as they will hold closer tolerances and resist wear better than other materials.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/400,090 filed on Aug. 1, 2002; No. 60/447,059 filed on Feb. 13, 2003;No. 60/447,061 filed on Feb. 13, 2003; and No. 60/452,032 filed on Mar.4, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to grinding machine components, andespecially relates to grinding components made of superhard materials.More particularly, the invention relates to tension rods, transfer ways,and spindles and spindle housings made of wear resistant superhardmaterials.

2. Description of the Prior Art

Conventional grinding machine components made of steel are well known inthe art, including one of the most common types of stainless steel thatincludes machine grade tool steel. However, as grinding machines havebecome more and more complex, and are now more capable of extremely highprecision grinding, the tolerances on those steel components have becomeincreasingly closer and closer. In addition, it is increasinglyimportant for a centerless grinding unit machine to be extremelyaccurate as well as simple to learn and set up for a grinding operation.For grinding unit machines that are highly accurate work holdingdevices, with 0.000030″ standard repeatabillty, as well as for thoseoptional machines with 0.000005″ to 0.000010″ repeatability, it isimportant for the grinding machine components themselves to be veryrigid and true to the shape. If the various components can havedimensions that are held to true, there is no need for an operator toindicate a work piece, which can save a lot of time on the job.

With regards to the spindles of centerless grinding machines, theconventional steel components become worn after continuous use. Grindingmachine components that are in a wear-induced state will have loweredtolerances, and the tolerances of the resulting work pieces will becomelower and lower until the work pieces will become unusable. At thattime, the grinding machine must be overhauled, and the originallyspecified tolerances will be once again achieved. However, in the veryrecent past, higher and higher tolerances are being required in order tomaintain quality control standards for manufacturing processes under ISO9001 procedures. Manufacturing capabilities also require less down timefor manufacturing processes in order to maintain profits and jobs forthe shop where the machine resides.

In an effort to maintain high tolerances for such grinding machines, itis important that wear-resistant machine tool components be utilized. Itwould therefore an advantage for the usage of wear-resistant grindingmachine tool components which will not wear, and thereby keep theextremely high tolerance of the grinding machine even after themanufacture of large numbers of machine parts.

Others have tried in the past to make more wear resistant grindingcomponents, but none have been able to make such highly precise and wearresistant components for this application, especially of the materialsbeing proposed in the present invention. Practitioners of those priorart inventions have become aware of certain problems which arepresented. One particular problem that has plagued operators has beenthat utilizing harder materials that will resist wear is more difficultto grind, especially to the desired tolerances sought by the presentinventors. There are complexities which give rise to warpage and havinga component that is out of true due to expansion and contraction.

Therefore, it would be of a great advantage to the grinding machineindustry if there was provided various wear resistant grinding machinecomponents made of superhard ceramic materials for holding closetolerances for a long time during operation, thereby reducing downtime,and saving costs.

SUMMARY OF THE INVENTION

In accordance with the above-noted advantages and desires of theindustry, the present invention provides various grinding machinecomponents made of superhard materials, including certain machine gradeceramics, including such materials as carbides, nitrides, borides,oxides, oxynitrides, or any other ceramic component. The component mayeither be a solid piece of ceramic or wear resistant material, or mayhave an insert or a piece of the wear resistant material adhered to ametallic substrate base for use within the machine. In that same regard,it is also envisioned by the present inventors that cermets, materialswhich have a gradient from a 100% concentration of ceramic at onesurface, and gradually changing into a 100% metal at the other surface,would be advantageous. Other cermets include ceramic infrastructures,infiltrated by molten metals, yielding a combination of ceramic andmetal in the same piece of material. Furthermore, coatings of carbides,nitrides and the like, as described above, may be utilized toeffectively coat a metal substrate, thereby giving a wear resistantcoating. These superhard materials overcome some of the aforementionedproblems with the prior art because they will hold closer tolerances andresist wear better than other materials.

The invention is particularly useful for applications of wear resistanttransfer ways, tension rods, spindles and spindle housings, among otherapplications. Although the invention will be described by way ofexamples hereinbelow for specific embodiments having certain features,it must also be realized that minor modifications that do not requireundo experimentation on the part of the practitioner are covered withinthe scope and breadth of this invention. Additional advantages and othernovel features of the present invention will be set forth in thedescription that follows and in particular will be apparent to thoseskilled in the art upon examination or may be learned within thepractice of the invention. Therefore, the invention is capable of manyother different embodiments and its details are capable of modificationsof various aspects which will be obvious to those of ordinary skill inthe art all without departing from the spirit of the present invention.Accordingly, the rest of the description will be regarded asillustrative rather than restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and advantages of the expectedscope and various embodiments of the present invention, reference shallbe made to the following detailed description, and when taken inconjunction with the accompanying drawings, in which like parts aregiven the same reference numerals, and wherein;

FIG. 1 is a side elevational view of a grinding machine made inaccordance with the present invention;

FIG. 2 illustrates a perspective view of a tension rod;

FIG. 3 is a perspective view a grinding rod made in accordance with thepresent invention;

FIG. 4 is a perspective view of a carbide pivot rod;

FIG. 5 is a top plan view of the grinding machine;

FIG. 6 is a bottom plan view of the grinding machine;

FIG. 7A is a side elevational view of the transfer ways in the grindingmachine;

FIG. 7B is a side cutaway view of the transfer ways;

FIG. 8A is a bottom plan view of the transfer ways;

FIG. 8B is a side cutaway view of the transfer way;

FIG. 9 is a top plan view of the way;

FIG. 10 is a carbide pivot rod;

FIG. 11 is a perspective view of a pivot rod;

FIG. 12 is a side elevational view of the pivot rod of FIG. 11;

FIG. 13 is an exploded side view of the pivot rod of FIG. 11;

FIG. 14 is a perspective view of a rod;

FIG. 15 is a side elevational view of the rod of FIG. 14;

FIG. 16 is a perspective view of a threaded shaft rod;

FIG. 17 is a side elevational view of the threaded shaft rod of FIG. 16;

FIG. 18 is a perspective view of a concentric shaft seal;

FIG. 19 is a threaded seal;

FIG. 20 is a side perspective view of a portion of a grinding machineillustrating the relative placement of the spindle housing; and

FIG. 21 is a side perspective view of a portion of a grinding machineillustrating the relative placement of another embodiment of the spindlehousing.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, and in meeting and exceedingthe objects and advantages being sought herewith, we now look to theappended drawings as illustrated in FIGS. 1-21 to more clearly defineand state the invention. Looking first to FIG. 1, there is shown agrinding unit generally denoted by the numeral 10, which includes aregulating roller 12 surrounding a spindle 18. The regulating roller 12receives the spindle 18 therethrough, and is rotatably mounted aroundthe spindle by bearings 20. Bearings 20 are held against the unit body16 by a tension arm 14.

A cross-sectional view of drive screw 22 is shown, and drive screw 22rotates about its longitudinal axis to operate drive gear 24, also shownin cross-sectional view in FIG. 1. As can be seen in FIG. 1, the spindle18 needs to be made of a rigid, non-flexing material to more carefullyand precisely hold the tolerance for the regulating roller 12. As thedrive screw 22 rotates and operates drive gear 24, spindle 18 rotatesregulating roller, and is preferably rigid enough to hold the tolerancesof the regulating wheel 12 during the dressing operation, which then (inturn) determines the repeatability of the grinding operation itself whenthe grinding wheel grinds the work piece.

Looking next to FIG. 2, a pivot rod is generally denoted by the numeral30, and is a round cylindrical grinding machine component having alocking slot 32 and a retaining ring groove 34 cut thereinto. A pivotpin hole 36 is drilled through the pivot rod 30. Pivot rod 30 will bedescribed more fully hereinbelow with reference to other drawings.

FIG. 3 illustrates a precision ground spindle made in accordance withthe present invention, and illustrates the preferred ground angles andouter diameter dimensions for use with a high precision grinder as thatavailable from Tru Tech Systems, Inc., of Mt. Clemens, Mich. The spindleis more fully described hereinabove with reference to FIG. 1, and thematerials useful for the spindle preferably include tungsten carbide,but may also utilize the materials listed hereinbelow, and may be doneso without undue experimentation on the part of one of ordinary skill inthe art in the act of reproducing the present invention.

FIG. 4 is a perspective view of a high precision lead screw made inaccordance with the present invention, and is generally denoted by thenumeral 50, including ground Acme threads 52 ground thereinto. Makingthe lead screw out of a super hard, rigid material is advantageousbecause it is this screw which drives the rollers, and will ultimatelydetermine the repeatability of the grinding unit itself.

In other words, the three components illustrated in FIGS. 2, 3 and 4,i.e. the pivot rod, the spindle and the lead screw, respectively, areall components of a high precision grinding machine which will benefitgreatly by being manufactured of extremely rigid, super hard materials,as discussed below. By manufacturing each of these components, as wellas other components which will hold the tolerances of the grinding unititself out of an extremely rigid material, such as tungsten carbide, thegrinding machine will ultimately be able to grind work pieces to lessthan a millionth of an inch. If these components are made out of anymaterials that can flex or bend at all, the tolerances will be lost, andthe dream of grinding work pieces to a millionth of an inch, reliablyand repeatably, dissolves away with the flexing/bending of these variouscomponents. The spindle, being made of carbide, will essentially notflex, and will hold the regulating roller in proper position so that thedressing operation can be close to perfect. When the pivot rod is madeof super rigid materials, the blade is held in perfect position,yielding a greater repeatability at higher tolerances than those whichwere available to a grinding operator before.

Turning now to FIG. 5, there is shown a grinding unit 60, including apivot rod 62 held in place with a pivot pin 64. Grinding unit body 66acts as a securement for the pivot rod 62, and is held in place withpivot pin 64, also shown in FIG. 2 above. Blade holder 68 is shown asbeing held against the pivot rod 62 by locking screw 70. The pivot rodis made of a super rigid and super hard material as described below withreference to the preferred materials utilizable for all the grindingmachine components envisioned by the present inventor.

Looking last at FIG. 6, there is shown a grinding unit 80, showing therelative placement of spindle 82 with regards to the regulating roller84 and bearings 86. The operation of the spindle has already beendescribed above with reference to FIG. 1, and similar principles apply.The spindle is preferably made of tungsten carbide or any of the othermaterials listed below. Any substitution of the materials may be donewithout undue experimentation on the part of one of ordinary skill inthe art practicing the present invention.

Looking now to the materials suitable and advantageous in accordancewith the present invention, the inventor contemplates useful rigidgrinding machine components made of any super hard material, including,but not limited to, carbides, nitrides, oxides, borides, ceramics,cermets, carbonitrides, carbon diffused materials, including steel,nitrides, borides, oxides, other metals and surface treated ferrouscompounds. All the preferred compositions listed herein are useful forthe present invention, although some are more preferred than others. Itis also envisioned by the present inventor that carburized steel isuseful, and that rigidity enhancing treatments prove useful. Suchrigidity enhancing treatments can include quenching (to produce amartensitic or bainitic case around a carburized steel part), reheating(for controlling and reducing the surface carbon content below thesaturation level), cold treating, and tempering.

Especially suitable materials for all the above-described grindingmachine components include all rigid ceramics made of carbides,nitrides, borides, oxides, carbonitrides, borocarbides, boronitrides,nitroborides, and especially tungsten carbide (WC), titanium carbide(TiC), combinations of WC and TiC and all other carbides, as well asother nitrides including carbonitrides (CN), silicon nitride (Si₃N₄),silicon carbide (SiC), and all other nitrides and nitro-carbides. Superhard materials also useful for the present invention include borides,such as boron carbide and other borides and boron nitride compositions.Of particular interest, and encompassing the preferred embodiment of thepresent invention, the grinding machine components are preferably madeof tungsten carbide and/or tungsten carbide alloys with other ceramicmaterials. The most preferred material for the present application isbasic high-grade tungsten carbide, although the other materials listedare equally useful. They may not be as advantageous as they will be moredifficult to machine into the grinding machine component, or thematerial may be more expensive than the tungsten carbide. Those factorsaside, their rigidity will all pass the necessities for the presentinvention.

Superior grinding machine components made then from a group of superhard, extremely rigid materials that will ultimately increase therepeatability of the grinding machine because all the components will beheld in position so rigidly, thereby keeping the tolerances of thegrinding machine during operation. In addition, these components will bevirtually wear proof for longer life of the grinding machine, and theywill allow for fast and high stock removal in the bargain. Increasedproductivity and keeping higher tolerances is the desired result in thegrinding industry, and the present invention will help achieve thosegoals.

Therefore, the present invention discloses superior grinding machinecomponents made from a group of super hard, extremely rigid materialsthat will ultimately increase the repeatability of the grinding machinebecause all the components will be held in position so rigidly, therebykeeping the tolerances of the grinding machine during operation. Inaddition, these components will be virtually wear proof for longer lifeof the grinding machine, and they will allow for fast and high stockremoval in the bargain. Increased productivity and keeping highertolerances is the desired result in the grinding industry, and thepresent invention will help achieve those goals. While the descriptionof the suitable materials may appear to be directed toward only some ofthe components, the following description relates to all grindingmachine components.

The present invention is preferably made of a bulk carbide, Grade 2material, although it may be made of any other known ceramic. Theceramic may be of a commercial grade of purity, and may be machinedutilizing some of the equipment further invented by the presentinventors earlier, known as the Tru-Tech Grinding Machine. Further in anattempt to achieve the objective of the present invention, a productionsteel center tension rod can be coated with a ceramic material, or theremay be an insert or sleeve placed around the tube of the tension rod.Clearly, because the objective of the present invention is to provide awear resistant surface for the tension rod, any means of having the wearresistant material on the surface which is subject to the wear is ofimportance, including surface treatments such as carburizing orcarbonitriding.

The present invention discloses the use of wear resistant materials forthe use of tension rods, and may include such things as carbides,nitrides, borides, oxides, oxynitrides, or any other ceramic component.The component may either be a solid piece of ceramic or wear resistantmaterial, or may have an insert or a piece of the wear resistantmaterial adhered to a metallic substrate base for use within themachine. In that same regard, it is also envisioned by the presentinventors that cermets, materials which have a gradient from a 100%concentration of ceramic at one surface, and gradually changing into a100% metal at the other surface, would be advantageous. Other cermetsinclude ceramic infrastructures, infiltrated by molten metals, yieldinga combination of ceramic and metal in the same piece of material.Furthermore, coatings of carbides, nitrides and the like, as describedabove, may be utilized to effectively coat a metal substrate, therebygiving a wear resistant coating.

These ceramics may come in varying grades, such as the preferred carbidematerial, and especially of Grade 2 carbide. It would also beadvantageous to incorporate cobalt or any other metallic component intothe overall composition of the ceramic in percentages of from about 1percent up to about 50 percent, both by weight. For example, theaddition of cobalt metal into a carbide bulk material prior to grindinginto a desired shape, such as the tension rod of the present invention,will help to prevent breakage in the event that the piece is everdropped on the floor. Preferable amounts of cobalt are from about 1 toabout 20 weight percent. Other metals may be desirable, includingvanadium, chromium, manganese, nickel, copper, zinc, molybdenum,cadmium, indium or tin. Furthermore, magnetic components such aspowdered iron, nibium, yttrium or other conventional permanent magnetsmay also be advantageously employed. These components would be mostuseful in the percent weight ranges of between about 1 and about 25percent of the resulting weight.

Grades 1 through 5 of carbide are especially useful, although any othercommercial or ultra pure grade of ceramic or carbide may be utilizedwithin the scope of this invention. Of the carbides, the most preferredinclude tungsten carbide (WC), titanium carbide (TiC), or combinationsthereof, or a boron carbide (BC). It is also envisioned that nitrides,including silicon nitride (Si₃N₄) or other carbonitrides may be usefulin particular situations due to their lubricious characteristics.Self-lubricating ceramics may also be of a special help, and of thosematerials silicon nitride is especially preferred. In addition, variousoxides, including alumina (Al₂O₃), or other oxides, or otheroxynitrides, are useful.

In addition to the use of ceramics on the wear resistant surfaces of thetension rod, the present invention further envisions carburizing andcarbonitriding for developing hard surfaces of steel parts, such as thetension rod. Although the basic principle of carburizing andcarbonitriding have remained relatively unchanged through the years,there are many changes in the technology of metals which have made forchanges in metallic structures, as well as their processing equipment,in order to achieve carburizing and carbonitriding. Generally,carburizing is effected by gas carburizing and hardening which willproduce a hard surface layer on a ferrous alloy. When using carburizing,a hardening agent is introduced into the surface of the alloy steel,thereby modifying the composition of the surface layer material itself.Thereafter, appropriate heat treatment provides for a case hardenedsurface layer with a core interior. This is especially useful foraustenitized ferrous material components which are brought into contactwith an environment of sufficient carbon to cause absorption of thecarbon at the surface and by heat diffusion creating a carbonconcentration gradient between the surface and the interior or core ofthe metal component itself. Carburizing may be done in a gaseousatmosphere (gas carburizing), a salt bath (liquid carburizing), or packcarburized by placing all of the surfaces of the work piece in contactwith a solid compound. Carbonitriding is done in a modified gascarburizing atmosphere, where the modification includes the introductionof ammonia into a standard gas carburizing atmosphere, thereby providingthe appropriate nitrogen.

Within the carburizing procedure, free carbon is then absorbed into thesurface layer of the work piece, which generally has a relatively lowcarbon content to begin with. The free carbon is derived either from itsgaseous or liquid source which comes into intimate contact with themetal surface. Absorption of the carbon into the surface layer may setup a concentration gradient, and carbon atoms may move by diffusion awayfrom the surface. Theoretically, then, the surface layer can attain acarbon content determined by the carbon potential, while the core willstay at a constant concentration of ferrous and other components. Inmost instances, the amount of carbon in the environment is controlled toachieve a desired carbon content at the surface of the metal.

With regards to carbonitriding, however, the requisite ammonia added tothe gas carburizing atmosphere dissociates to produce hydrogen andmonoatomic nitrogen. The nitrogen is then absorbed into the surface ofthe work piece, along with carbon from the carburizing gas. Generally,carbonitriding is most advantageous as it is used in making a shallowcarbonitrided surface because the nitrogen inhibits the diffusion ofcarbon throughout the steel, although it enhances hardenability, whichfavors the attainment of a very hard case that is easily polished andhighly wear resistant. In addition, nitrides are formed and theparticular hardness of those nitrides leads to even more wear resistantthan is attributable to a maximum matrix hardness alone.

However, it must be realized that the preferred material for the presentinvention is a carbide, which is a Grade 2 material. A stock piece willbe machined into a desired shape to be used as a tension rod in agrinding machine application. Furthermore, in an attempt to provide awear resistant surface as desired by the present invention, there aremany heat treatments, quenching treatments and other surface effectswhich can be implemented in order to provide a more wear resistantsurface for the tension rod. All of these treatments, or inclusions ofceramics and the like, are designed to do one thing . . . . to providewear resistance for the tension rod so that it will hold its extremelyhigh tolerances. The treatments that we are discussing do not add to thedimension of the particular grinding machine component, rather they areatomically absorbed into the bulk of the material and can be usedinterchangeably with production steel components for the grindingmachine.

In addition to the above description of the use of ceramics and the useof surface treatments such as carburizing, carbonitriding and heatannealing or quenching, there are also various procedures for increasingthe adhesion on the surface of a metal substrate to any of theabove-mentioned wear resistant materials and/or treatments. Inparticular, pre-oxidation prior to any adhesion or to the subjection ofgas carburizing provides a maximum carbon and nitrogen absorption anddiffusion, based on thermodynamic and kinetic considerations.Furthermore, there may be additional layers of metal, such as nickel ortin, which can be plasma sprayed, sputtered, plasma discharged, or anyother method of applying a very thin coating of an adhesion layer ontothe steel core component prior to receiving the ceramic, or a gastreatment such as carburizing. Gas treatments, such as sulfonation, mayalso be employed to help adhesion of subsequent layers. In addition,ionic chemical treatments may also add to the adhesion factor, or may beutilized for surface hardened components. All of these hardened layerswill provide a superior contact performance for rolling and slidingoperations, and will provide better specifications and equipmentconsiderations which are essential for reproducible process executions,including grinding of work pieces.

Looking now to FIGS. 7A and 7B, there can be seen in FIG. 7A a grindingmachine generally denoted by numeral 90, having a work platform 12positioned above a machine base 94. When taken along lines A-A, FIG. 7Bshows a cutaway elevational view of the portion of the grinding machinewhich illustrates the relative placement of the ways. As shown in FIG.7B, work platform 92 is positioned above machine base 94, and isseparated by a pair of v-shaped ways and flat surface ways. Flat way topmember 96 slides atop flat way bottom member 98. At the other end of theplatform a v-shaped way top member 100 slides atop the v-shaped bottommember 102. As shown in these figures, any configuration of the wearresistant way members disclosed in the present invention may beutilized. This may include a solid carbide Grade 2 material way, or mayinclude a cermet or a carbide insert placed over a metal substrate to beused in place of a metal way.

Looking next to FIGS. 8A and 8B, there is shown a top plan view of agrinding machine generally denoted by numeral 110 in FIG. 8A. The workslide 112 is slideably mounted onto the work base 118. The work platformslide 116 is best seen in FIG. 8B, and is slideably mounted on top ofthe work base 118. It is suspended by a flat way and a v-shaped way. Thev-shaped way top member plate 120 slides atop the v-shaped way bottommember plate 122, while the flat way top member plate 124 slides on topof flat way bottom member plate 126.

With reference to FIG. 9, there is shown an insert made of the wearresistant material in accordance with the present invention, which maybe used as a surface piece on top of a metal substrate of the wayitself. FIG. 9 generally denotes a way insert by numeral 130, andincludes a countersunk hole 132 within the bulk of the way insert 130.The way insert upper surface 134 and way insert lower surface 136 areground smooth for sliding capabilities, in the instance of upper surface134, and for proper adhesion with regards to lower surface 136 to anunderlying substrate piece. The metal substrate is not shown in thesefigures, although the use of carbide inserts is common in certainindustries.

Looking at FIG. 10, there is shown a side elevational view of a tensionrod, suitable to be received by a tension rod arm (not shown). Thetension rod is basically of a cylindrical structure and has alongitudinal axis down the center of the rod. The rod is preferablyperfectly round, so as to impart a uniform force on the work piece as itis rolling around against the grinding wheel (also not shown). In themost preferred embodiment, the tension rod is a little more than 5½inches long, with approximately a ¾ inch diameter. There is a hollow,machined-out portion which is approximately 1 inch and is about a thirdof an inch in diameter, in order to be received on the tension rod arm.Further, there are machined-out portions of the other end of the tensionrod from the hollow end, and they are respectively about ½ inch and morethan 1/4 inch, suitable for being received by other components in thegrinding machine. Although the tension rod is currently being made fromproduction steel, it is thought by the present inventors to be anadvantage to provide a new tension rod material which is more wearresistant than the conventional steel pieces.

Looking now to FIG. 11, there is shown a spindle assembly forutilization in a grinding machine, and the spindle assembly is generallydenoted by the numeral 140. Spindle assembly 140 includes a spindleshaft 142 with a threaded shaft 144 press fitted over a distal spindleextension on the distal end of spindle shaft 142. At the proximal end ofthe spindle shaft 142, there is a press fitted concentric collar 146where the concentric collar 146 includes a concentric collar aperture147 (shown in FIG. 18) through the center of collar 146 ready to bepress fitted over a proximal spindle extension 152 which is integralwith spindle shaft 142. A threaded tip 148 is press fitted onto proximalspindle extension 152 in order to complete the spindle assembly. As canbe seen with combined reference to FIGS. 11 thru 13, it is envisioned bythe inventors that the spindle shaft 142 may be made of thewear-resistant material, or may be coated with the wear-resistantmaterial, such that other grinding machine components which turnregularly over the spindle shaft 142 will not wear down the surface andthereby reduce the tolerance of spindle shaft 142. Spindle shaft 142 ismachined to form a desired shape and has a distal spindle extension 150to receive a threaded shaft collar 154 which is integral with threadedshaft 144. Threaded shaft collar 154 and threaded shaft 144 areconventionally made of a machine grade tool, but may also be made of awear-resistant material or a surface coated high strength core. Lookingto the proximal end of spindle shaft 142, there is a proximal spindleextension 152 which has been machined and is also made of thewear-resistant material and or wear-resistant material coated over asteel core. A threaded tip 148 is press fitted over the proximal spindleextension, and adds great strength and usability to the spindle shaftitself.

Looking next to FIGS. 14 and 15, there are shown detailed drawings ofthe spindle shaft 142 itself, with the distal spindle extension 150 andproximal spindle extension 152 extending therefrom. Of course, differentconfigurations for the spindle assembly itself may be utilized fordifferent grinding machines, although this is a standard spindle shownin FIGS. 14 and 15.

Looking now to FIG. 16, there is shown the threaded shaft 144 with itsintegral threaded shaft collar 154. The collar 24 has an interiordiameter which is of a particular shape, depth and wall thickness inorder to be press fit over the distal spindle extension 150 shown in theprevious FIGS. Although the threaded shaft 144 is preferably made ofmachine grade steel, threaded shaft 144 may also be made with a steelcore, and have a wear-resistant surface created thereon in order toallow for wear-resistant usage of the grinding machine. A wear-resistantcoating could be sputtered, discharged, plasma sprayed, or created onthe surface of a steel component. Such techniques are known in the artfor making titanium nitride coatings, and the like. Such a coatedcomponent would have a resulting high tolerance wear ratio.

FIG. 17 illustrates a side elevational view of a threaded shaft 144,having a grinding center and a smooth portion 154 at the distal end. Thethreaded portion is preferably a ¾ 16 N.F.-3 thread, right hand, with apitch diameter of 0.7094 to a 0.7062.

Looking next to FIG. 18, there is shown a concentric collar 146 having aconcentric collar aperture 147 extending axially through the collar 146in a diameter sufficient to be press fit onto the spindle shaft 142itself. In this particular embodiment, the concentric collar 146 has aspecific shape and dimension, and is not to be limited in the scope ofthis invention by the particular embodiment shown in FIG. 18. Again, ahigh strength steel core may be utilized with a wear-resistant carbide,nitride or oxide coating or insert placed on or around the collar forwear-resistant itself.

FIG. 19 shows the threaded tip 148 which is to be press fitted onto theproximal spindle extension 152, in order to be complementary to othergrinding machine components. It is preferable to have this componentmade of a high grade machine steel in order to impart strength onto thespindle shaft 142 when it is in use when the grinding machineapplication itself.

Therefore, in accordance with the present invention, there is discloseda complete wear-resistant spindle assembly having a concentric collarpress fit thereon along with a threaded shaft and threaded shaft collarwhich achieves the objectives and advantages of the present invention.Whether the wear-resistant feature is achieved via a bulk material whichis generally wear-resistant, or whether a high strength steel core isutilized with a wear-resistant coating thereon, the prescribed spindleassembly as shown in FIGS. 11 thru 19 will achieve those objectives andmaintain the tolerance of the grinding machine after many hours ofoperation.

Even though a particular embodiment of the spindle assembly has beenshown in FIGS. 11 thru 19, it must be understood that the scope of theinvention is not be limited by the exact configuration of the spindleassembly, rather conventional spindle assemblies utilized in traditionalgrinding machines may employ the present concept of this invention inorder to maintain their tolerances and achieve better workability, morehigh tolerance work pieces resulting therefrom, and less down time inthe machine itself.

FIGS. 20 and 21 are both illustrations of a spindle housing as part of agrinding machine in accordance with the present invention, and thegrinding machine is generally denoted by the numeral 160. Grindingmachine 160 includes a spindle housing generally denoted by the numeral162, including a spindle housing arm 164 and a spindle housing sleeve166 to be received by the spindle housing arm 164. FIGS. 20 and 21 areessentially the same, but they illustrate various embodiments of thespindle sleeve. FIG. 20 shows a round sleeve, while FIG. 21 shows asquare housing.

The spindle housing of FIGS. 20 and 21 are advantageously made of thesame materials as those described above. For the sake of brevity, thatdescription will not be repeated here, but applies equally. One of thereal advantages of the spindle housing being made of carbide or otherceramic materials is that the extra weight makes for a more stablemachine, which helps to keep the tolerances higher for a longer periodof time.

In summary, numerous benefits have been described which result fromemploying any or all of the concepts and the features of the variousspecific embodiments of the present invention, or those that are withinthe scope of the invention. The superhard materials act perfectly toresist wear and to provide a more repeatable grinding operation.

The foregoing description of a preferred embodiment of the invention hasbeen presented for purposes of illustration and description. It is notintended to be to be exhaustive or to limit the invention to the preciseform disclosed. Obvious modifications or variations are possible inlight of the above teachings with regards to the specific embodiments.The embodiment was chosen and described in order to best illustrate theprinciples of the invention and its practical applications to therebyenable one of ordinary skill in the art to best utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the claims which are appended hereto.

INDUSTRIAL APPLICABILITY

The present invention finds industrial applicability in the grindingmachine industry.

1. A wear resistant grinding machine component, comprising: a grindingmachine component made of a solid ceramic ial selected from the groupconsisting of carbides, nitrides, oxides, borides, cermets,carbonitrides, and combinations thereof.
 2. An extremely high precisionwear resistant grinding machine component for a high precisioncenterless grinding machine, comprising: a grinding machine componentmade of a solid piece of an extremely rigid and very hard, non-flexingmaterial select from the group consisting of ceramics, carbides,nitrides, borides, oxides, oxynitrides, carbonitrides, alumina, cermets,nitrides, borides, oxides, and combinations thereof, wherein thegrinding machine component may include the entire component being madeof a ceramic material, a sleeve of solid ceramic material adhered over ametallic substrate base, and a grinding machine component made of acermet material, formed into a grinding machine component.
 3. Thegrinding machine component of claim 1, wherein the grinding machinecomponent is selected from the group consisting of tension rods,transfer ways, spindles, spindle housings, pivot rods, threaded shaftrods, concentric shaft seals, lead screws, and combinations thereof. 4.The grinding machine component of claim 1, wherein the grinding machinecomponent is non-flexing and maintains a very high tolerance of fromabout 0.000005 inch to about 0.000030 inch.
 5. The grinding machinecomponent of claim 1, wherein the grinding machine component enables arepeatability factor of from about 0.000005 inch to about 0.000030 inch.6. The grinding machine component of claim 1, wherein the grindingmarine component is made of a metallically infiltrated cermet materialmade from a spongy ceramic and then infiltrated with a molten metalwhich is thereafter allowed to solidify within the matrix of the spongyceramic.
 7. The grinding machine component of claim 1, wherein thegrinding machine component further includes a metallic componentincorporated into the ceramic material to increase the strength of thecomponent.
 8. The grinding machine component of claim 7, wherein thegrinding machine component further includes a metallic component in theceramic material selected from the group consisting of cobalt, vanadium,chromium, manganese, nickel, copper, zinc molybdenum, cadmium, indium,tin and combinations thereof.
 9. The grinding machine component of claim7, wherein the grinding machine component further includes the metalliccomponent in a concentration of from about 1 to about 50 percent byweight.
 10. The grinding machine component of claim 1, wherein theceramic grinding machine component further includes a magnetic componentincluding a component selected from the group consisting of powderediron, niobium, yttrium and combinations thereof.
 11. The grindingmachine component of claim 10, wherein the grinding machine componentfurther includes the magnetic component in a concentration of from about1 to about 25 percent by weight.
 12. The grinding machine component ofclaim 1, wherein the grinding machine component may be formed into agrinding machine component by forming a hard surface layer by a methodselected from the group consisting of carburizing and carbonitriding.13. The grinding machine component of claim 12, wherein the grindingmachine component formed into a grinding machine component bycarburizing is accomplished by carburizing by a method selected from thegroup consisting of gas carburizing by placing in a carburizing gaseousatmosphere, pack carburizing by placing all the surfaces in contact witha solid compound, and combinations thereof.
 14. The grinding machinecomponent of claim 12, wherein the grinding machine component is formedinto a grinding machine component by carbonitriding by dissociatingammonia into hydrogen and nitrogen.